Hydraulic balancing device



Oct i957 M..J. CURRAN, JR

HYDRAULIC BALANCING DEVICE Filed March 29, 1966 FIG.

FIG. 3

INVENTOR MARTIN J. CURRAN JR.

ATTORNEY United States Patent Oflfice 3,348,8 l Patented Oct. 24, 1967 3,348,810 HYDRAULIC BALANCING DEVICE Martin J. Curran, Jr., 3035 Dunbar St.,

Attica, N.Y. 14011 Filed Mar. 29, 1966, Ser. No. 538,295 8 Claims. (Cl. 254-433) This invention relates to a hydraulic or pneumatic balancing mechanism and to valves therefor, in balancing elements which are adapted to contact and move or stabilize an object. It often happens that if a series of elements, e.g. pins are utilized to lift an object, one of the pins may contact the object before the other pins, and if these pins are rigidly mounted, the result is that the object to be moved, i.e., lifted, is canted or tilted. In many applications this is very deleterious to the operation contemplated. One example is the lifting of flasks from patterns in the metal casting industry.

It is therefore an object of this invention to provide a hydraulic or pneumatic balancing mechanism which automatically operates to transfer the lifting, stabilizing or moving action of any one or more elements equally to the other elements, pins, or other lifting means, and the invention is carried out by providing hydraulic cylinders wherein the lifting elements, e.g. pins act as pistons. Therefore if a single pin of a set contacts the object to be moved it will be retracted thereby, applying pressure to fluid in the cylinder and transferring the pressure to the other lifting pins until a balanced condition is achieved, whereupon the valves provided automatically close and the pins at various degrees of extent will therefore act with equal force thereafter on the object to be lifted, stabilized or moved, such as a molding flask, or the like.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which:

FIG. 1 is a view in elevation illustrating a set of lifting pins for a flask;

FIG. 2 is a cross sectional view on an enlarged scale illustrating the balancing mechanism therefor, and

FIG. 3 is a view similar to FIG. 2 but showing a modification.

Although this invention may take many forms and particularly the lifting means may be in different forms, and the applications may be of any kind desired, the invention has been illustrated as specifically applied to lifting a flask which is used in the metal casting industry. It is to be understood of course that the patterns, etc. are utilized in a conventional Way in conjunction with the flask 10 which is essentially an open container which is necessary to be lifted during the casting processes. The lifting means is energized by power means, not shown, through a member 12 in this case lifting in the direction of the arrow in FIG. 1. The member 12 is connected to a bar, platform or other support 14 upon which are mounted a plurality of members in the nature of fluid cylinders, these being all alike and indicated at 16, 16. In the present case there are four of these cylinders arranged at the corners of flask 10 and each is provided with its piston 18, 19. The reference numeral indicates a casing for the valve arrangement shown in detail in FIG. 2.

When the flask is to be lifted, if there are any irregularities concerned with relation to the position of the flask, etc. and one or more of the pistons 18, 18 should strike the bottom edge of the flask before the other pins, the valve arrangement in the present case will ensure that such pins will retract and apply fluid pressure to the other pins, thus causing a very efiiciently and quickly balanced arrangement between the pins so that all of them will then lift the flask with equal pressure and motion.

Referring now to FIG. 2 it will be seen that there are fluid passages which may be in the form of pipes 22, 24 from the bottom of each cylinder 16, 16 into the valve housing 20. Pipe 22 leads into a chamber 26. This chamber has an outlet 28 normally closed by a ball or other type of valve 30 under influence of spring 32. The passage in which the ball 30 and spring 32 are located communicates with a larger chamber 34 near the top of the housing. The chamber 26 also communicates with respect to another chamber 36 which is smaller than chamber 34 and is located in the bottom of housing 20, it being apparent that the normally closed valve member 38 under the influence of spring 40 will stay closed with pressure in chamber 26, but the valve at 30 will open.

This construction is repeated for each of the pins regardless of hoW many of them there are, it being seen that the pipe 24 leads into a chamber 42 having a springpressed valve 44 leading into chamber 34 in the same manner as before described and also the valve member 46 will remain closed under pressure from chamber 42 but will open under pressure from chamber 36.

In the top of the housing 20 there isa piston 48 which is spring-pressed downwardly by a spring 50, the tension on the spring being adjustable by a member 52 under influence of the adjusting screw or the like 54.

The piston 48 is provided with a rod 56 connecting it to an abutment 58 running through chamber 34 and through a small extension thereof as at 60 and it will be seen that the abutment 58 closes ofi chamber 60 from chamber 36 when the pressure on the piston 48 causes the same to rise against the action of the spring 50. However when spring 50 overbalances the pressure in the chamber 34, the rod 56 will descend providing communication between chamber 34 and chamber 36 through chamber 60.

The operation of the device will be clear because a relative downward pressure on any one of the pins causes hydraulic pressure to extend through say for instance pipe 22 into chamber 26 and thence into chamber 34. As long as the abutment at 58 is removed from its seat 62, pressure will be applied on the valve member 46 and thence to another or all the other cylinders and pins. As the pressure builds up however, the piston 48 must rise against the action of its spring 50 eventually closing off chamber 60 from chamber 36 and at this point the balance of the system is achieved due to the fact that the pins originally not under pressure, will be under downward pressure within a short time after retraction of the first pin that contacts the object to be moved. Hence what might be referred to as a back pressure will be applied as for instance through pipe 24 into chamber 42, and thence into the chamber 34.

The modification shown in FIG. 3 operates the balance valve by electric means rather than directly by pressure. In this figure the chambers at 26 and 42 are the same as before as well as chamber 34, and like parts are identified by like numerals, and the action as to balancing and stabilization is similar. However, in this case the valve at 62 closes a normally open chamber 64 by seating at 66 under influence of a solenoid 68 or like electrically controlled device. Valve 62 is connected to the core 70 of the solenoid by a rod 72.

A pressure responsive diaphragm 74 transmits pressure in chamber 34 to a piston or the like 76 normally in dotted line position due to spring 78, the force of which is adjustable by screw 80 or the like. As the piston rises, it carries with it movable contact 82 for engagement with a fixed contact 84, closing the circuit shown and energizing the solenoid to pull valve down and close chamber 64. When pressure is lessened in chamber 34, spring 78 pushes piston 76 and contact 82 down, thus opening the circuit and allowing spring 86 to push rod 72 up and open 3 the valve 62 to re-establish communication between chambers 34 and 64.

Having thus described my invention and the advantages thereof, I do not Wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. An apparatus comprising a support, a plurality of elements movably mounted thereon, and a balancing hydraulic system connecting and in part controlling the motion of said elements under external pressure,

a cylinder for each element, each element applying increased pressure to its cylinder as it retracts with respect thereto under external pressure,

and a central valve system connected to the cylinders and being effective to transfer pressure from any cylinder under such increased pressure to any cylinder under lesser pressure,

said valve system including a balance valve effective to cease such transfer when the exterior pressures on the several elements is substantially equal.

2. The apparatus of claim 1 wherein the central valve system includes first and second chambers, first one-way normally closed valve means from each cylinder leading into said first chamber, said balance valve defining a normally open valve leading from said first chamber to said second chamber, second one-way normally closed valve means leading from said second chamber to said cylinders, whereby increased pressure in any cylinder opens its associated first valve means and the second valve means associated with any cylinder under lesser pressure to transfer pressure to said any cylinder under lesser pressure via said balance valve to balance the pressure in said cylinders, balancing of said pressure closing said balance valve.

3. The apparatus of claim 1 including hydraulic means to close the balance valve.

4. The apparatus of claim 1 including electric means to close the balance valve.

5. The apparatus of claim 1 including electric means to close the balance valve including a pressure responsive movable contact and a fixed contact inthe path thereof.

6. The combination of an object to be moved and means to move it including a series of like retractable spaced elements, a support for the elements, means exerting pressure of said elements, and means to move the support toward the object, wherein the elements may fail to contact the object simultaneously,

of means associated with said elements to increase pressure on any element not contacting the object derived from any element contacting it and being retracted by such contact,

and means to balance the pressure on all the elements When said elements are in supporting contact with said object.

7. The combination of calim 6 including hydraulic means controlling the pressure balancing means.

8. The combination of claim 6 including combined hydraulic and electric means controlling the pressure balancing means.

References Cited UNITED STATES PATENTS 2,859,591 11/1958 Zimmerman 60-97 3,265,357 8/1966 Schilling 25493 X OTHELL M. SIMPSON, Primary Examiner. 

1. AN APPARATUS COMPRISING A SUPPORT, A PLURALITY OF ELEMENTS MOVABLY MOUNTED THEREON, AND A BALANCING HYDRAULIC SYSTEM CONNECTING AND IN PART CONTROLLING THE MOTION OF SAID ELEMENTS UNDER EXTERNAL PRESSURE, A CYLINDER FOR EACH ELEMENT, EACH ELEMENT APPLYING INCREASED PRESSURE TO ITS CYLINDER AS IT RETRACTS WITH RESPECT THERETO UNDER EXTERNAL PRESSURE, AND A CENTRAL VALVE SYSTEM CONNECTED TO THE CYLINDERS AND BEING EFFECTIVE TO TRANSFER PRESSURE FROM ANY CYLINDER UNDER SUCH INCREASED PRESSURE TO ANY CYLINDER UNDER LESSER PRESSURE, SAID VALVE SYSTEM INCLUDING A BALANCE VALVE EFFECTIVE TO CEASE SUCH TRANSFER WHEN THE EXTERIOR PRESSURES ON THE SEVERAL ELEMENTS IS SUBSTANTIALLY EQUAL. 